Micrometer



Jan. 19, 1954 LASERSQN I 2,666,263

MICROMETER Filed July 5, 1952 IN V EN TOR.

whim

bring the work to the finish. size;

Patented Jan. 19 1954 V U MICRQMETER Frederick M.;Laserson ,Ls Angeles, Calif. Application July 5, 1952, Serial No. 297,223

4 Claims. (01.33-164) My invention relates to improvements in micrometers.

" An object of the invention is to provide a micrometer usable in every way as a conven- 'tional micrometer but which can, in addit on, beused to save time and eliminate the possibility of errors when taking measurements during the progress of turning, shaping, boring and'the like.

Another object of the inventionis toprovide a micrometer where-the required finish measure-' ment is set in advance on a conventional scale and locked on the micrometer, and all work measurements'taken on an auxiliary scale which shows only the amount of,cutting necessary to In the accompanying "draw' 'gs I show complete examples of the physical embodiments of my invention devised to illustrate in a simple manner the practical application of the principles of my invention. It should, however, be understood that changes may be made within the scope of what is claimed without departing from the spirit of the invention.

In the drawings:

Figure 1 is a side view of a caliper form of the invention.

Figure 2 is an enlarged longitudinal section of an inside-measuring micrometer.

Figure 3 is a longitudinal part view and section of the main thimble of the micrometer.

Figure 4 is a longitudinal part view and section of the auxiliary thimble.

Figure 5 is a cross section along a line 5-5 of Figure 3.

Figure 6 is a cross section along a line 6--6 of Figure 4.

In these views, numeral 1 designates the usual frame, 3 is the spindle and 9 the anvil. 10 is the usual sleeve or barrel with its graduations which cooperate with graduations H on a rotary thimble l5. Axially continuous with the spindle 8 is a micrometer-screw l2 which travels in nut l3 of the barrel l0, and is held integral with the thimble M. The parts of a micrometer thus far described being mainly old and well known construction, an extended description of the mechanism is omitted.

In my invention I split the thimble into two portions. The conventional portion l4 remains attached to and is coaxial with the spindle 8, which, as stated before, travels by a micrometerscrew 12 in the bore of the barrel l0, and is held integral with the thimble M. In threaded engagement with the thimble I4 'I devise an auxiliary thimble l5, the thread having the same lead as that of the micrometer-screw.

- f The auxiliary thimble i5 is provided with an indent "5 for engagement with a pin I! in a locking ring I8. The locking ring I8 is mounted slidable on the main thimble M, with its movement limited by a slot [9 through which the pin IT projects.

6 The main thimble i4 is provided with graduations which cooperate j with graduations 2| on the auxiliary thimble l5; calibrated to read 0 when the two thimbles are locked or are ina locking position.

; When thus locked, the instrument serves as a conventional micrometer; readingsbeing taken in the usual manner on the scale of the barrel It in conjunctionwith the calibrations on the auxiliary thimblejl.

Numeral 22 ishows aknurled clamping ring:

including a brake shoe 23 resting partly in. a transverse groove 24 in the auxiliary thimble I5 and partly in an eccentric portion 25 of the bore of the ring. The brake shoe is pressed into frictional contact with the barrel Hi by a roller 26 when the clamping ring is rotated slightly.

For taking measurements on work in process of being reduced to size, the two thimbles are aligned to 0 on the calibrations 20 and 2| and locked as a unit by sliding the locking ring l8 axially into the engaging position. The micrometer is thereafter set to the finish measurement required on the calibrations I 0 and II, and the auxiliary thimble l5 firmly locked on the barrel ID by rotating clamping ring 22. The locking ring I8 is then slid to disengage the two thimbles.

Measurements are now taken of the work as the cutting progresses, by reading on the scale 20 and 2|, which shows at each reading the exact amount of material necessary to be removed to bring it to the finish size which would be 0 on the scale 20 and 2|.

Figure 2 shows the invention embodied in an inside-measuring micrometer. The barrel in has the usual graduations engraved upon it, and terminates in a knurled head 27. Through the knurled head emerges an interchangeable spindle 28 slid through a bore in the micrometerscreW i 2 and retained against a shoulder 29 on the micrometer-screw by a cap 30. The cap also holds a contact 3| or it can carry an extension measuring rod of any length. This construction can be adapted for use as a depth gauge by incorporating a fiat base, shown by dotted lines 3|.

The method of reading the micrometer for depth and bore measurement in production work differs from the caliper method inasmuch as the cutting is for enlarging the measurement.

In these cases, instead of setting the micrometer to the finish size required the micrometer is set to an arbitrary minus measurement, say .050 less than the finish size, and the progress readings taken on the auxiliary scale outwards from 0 until the .050" mark is reached; the interim measurements showing the amount of stock to be removed to bring to the finish measurement.

What I claim is:

1. In a mieremeter, including a spindle, :a micrometer-screw, a cooperating barrel and a cooperating thimble: an auxiliary thimble attached to the first said thimble; graduations showing the amount of movement of the said thimble relatively to the auxiliary thimble; graduations showing the amount of movement of the auxiliary thimble relatively to the said barrel; means for optionally engaging the two thimbles to move integrally as one thimble; and means for optionally engaging the auxiliary thimble with the :sai'd barrel :to prevent relative movement 'of the auxiliary thimble and the said barrel.

'2. In a micrometer; including a :spindle, a

'micrometersserew, fa cooperating -:luaurrel and a cooperating thimble: an auxiliary thimble engaged by inicmmeter-screw"Ithr ea'ds with the first said "thimble; graduations showing the amount of axial displacement 6f the first said thimble relatively to :the auxiliary lth'imble; graduations showing the amount of axial displacement of the auxiliary thimble relatively to the said barrel; means for optionally engaging the two-thimbl'es to rotate integrally :as :one thimble; and 7 means for aop'tionally @engaging the auxiliary thimble with the said barrel to pre-vent rla'tive movement for the auxiliary 'thirrlble and the barrel.

Number 3. In a micrometer, including a spindle, a micrometer-screw, a cooperating barrel and a cooperating thimble: an auxiliary thimble engaged by micrometer-screw threads with the first said thimble; graduations on the first said thimble and cooperating graduations on the auxiliary thimble; graduations on the auxiliary thimble and cooperating graduations on the said barrel; a clamp ring for optionally holding the auxiliary thimble nnrotatable on said barrel; ,and means for optionally locking-the auxiliary thimble to the first said thimble to provide integral move- 'ment.

'4. In a micrometer, including a spindle, a micrometer-screw, a cooperating barrel and a 00- operating tl-fimble: an auxiliary thimble engaged by micrometer-screw threads with the first sa'id thimble; graduations on the first said thim- =ble and cooperating graduations on the auxiliary thimble; graduations on the auxiliary thimble :and cooperating graduations on the said barrel; a clamp ring for optionally holding the auxiliary thimble unrotatable on said barrel, and means ior "optionally locking the auxiliary 1thimb1e to the (first said tmmhle; said lockin sem- 1prisinga pin moving in a longitudinal slot, carri d. by :an axially 'slidab e rin 0 the first sai thimble, and g n :in a ma ching indent in the auxiliary thimble.

.EBEDERICK 'Beferences Cited in {the file of this patent UNITED "STATES PATENTS Name Date 672,622 Isherwoo'd Aprli23p1901 

